Gauge for setting internally threaded blanks in a thread grinding machine



March 29, 1938. 2,112,491

GAUGE FOR SETTING INTERNALLY TfiREADED BLANKS IN THREAD 'GRIENDINGMACHINE 'o. HINTZ Filed Jan. 4, 1937 Patented Mar. 29, 1938 PATENTOFFICE 2.112.491 GAUGE ron' sn'rrma m'rmmm! THREADED BLANKS IN A THREADGRINDING MACHINE Otto Hints, Frohnan, near Berlin,

Germany, v a

signor to Herbert Lindner, Berlin-Wlttena Germany Application January 4,1931, Serial No. 119,031 In Germany-July 16, 1938 6 Claims. (01. 33-472)ing machines, but such means requires the use of a complicatedarrangement and also requires several operations. The method generallyused requires that a thread gauge be inserted between the centers of thegrinding machine, and a positioning gauge. which is mounted on themachine to swing toward and from the axis of the blank, is brought intocontact with the preformed thread on the blank and is adjustedlongitudinally to flt..in the groove of the thread. This gauge isdefinitely positioned with respect to the grinding wheel in such mannerthatthe distance longitudinally of :the axis of the grinding wheelbetween the edge of the-wheel and O the center of the gauge is amultiple of the pitch of the screw to be ground. ,After this setting ofthe positioning gauge relative to the thread gauge, the positioninggauge is swung away from the thread gauge and the latter is removed. Theblank is now fixed'in the machine and the positioning gauge swung'intocontact withi'the blank which is then adjusted so that the gauge pointenters the thread groove tothe greatest possible extent. The.positioning gauge is now swung away from the work and the grinding wheelbrought'into contact therewith. While this very complicated arrangementmay be used for blanks with external threads, it cannot be used forblanks having pre-i'ormed internal threads because one cannot tell withaccuracy by direct vision what the position of a gauge point is in ahollow object, nor can the gauge be swung out of the way if used in suchan object.

One important object of the present invention is to provide a novelgeneral constructionbr settin auge for positioning internally threadedblanks in athread grinding machine.

A second important object of the invention is to provide novel means insuch a gauge arrangement for accurately determining the properpositioning of the gauge point'in the blank.

A third important object of the invention is to provide a novelarrangement whereby the gauge point may be set in desired relation tothe cutting plane of the milling cutter.

with the foregoing and other objects in view. the invention consistsin'the details of construction andin the arrangement and combination ofparts to-be hereinafter more fully set forth and Y 8' adjustable Indescribing the invention in detail, reference will be had to theaccompanying drawing forming part of this application, wherein likecharacters denote corresponding parts in the several. views. and inwhich- Figure 1 illustrates a side elevation of a portion of a threadmilling machine having the novel gauge means applied thereto, the latterbeing shown partly in section;

Figure 2 illustrates an enlarged plan view, partly in section, andshowing a portion of a grinding machine head with the invention plied;and

Figure 3 illustrates a greatly enlarged faceview of a scale arrangementused herewith.

While the invention may be appliedto any hereshown as carried by thehead 3. Arranged in the usual manner a grinding spindle i provided witha pulley 6 The pulley Bis connected by a-belt 5 with a pulley 4, whichmay be driven by any suitable means such as a motor (not shown). Thespindle i carries the grinding wheel 8 which has its profile shaped inaccordance with the profile of the thread to be ground. As here shown,the wheel 8 is profiled for grinding a V-thread, but the invention isnot limited to any particular form of thread and the form here given thegrinding wheel is merely indicative of some form of' thread grindingwheel. In order to dress the grinding wheel so that its profile centerplane 33' will be accurately positioned relative to the head 3, adressing device 1 is mounted on the head to swing on the axis 8.Thisdevice is provided with the usual diamond point wheels.

All of the foregoing parts are common in thread grinding machines sothat more detailed disclosure of these parts is not necessary, sincethey are all old and well known.

The invention itself consists of a base member 9 which is fixed on thehead 3 and is provided convenient part of -a grinding machine, it is todesired position'for dressing the crometrically adjusted on the base 8.An arm -Because of these facts, the angle of the point II is pivoted atone end to the carriage 9b by a pivot l2 and a stop II is provided onthe carriage so that, in inactive position, the arm ll may rest against.this stop. In its active position, which is about 90 from its inactiveposition in an anti-clockwise direction, the arm is held in setpositionby an index pin it carried by the in the carriage lb. Carried bythearm II is a guide member Ila which is provided with a longitudinalslot Mb. The lower side of this guide lid is V-shaped in cross sectionand on this lower side is held a carrier member I! having acorrespondingly shaped groove. A screw it passes through the slot liband holds the carrier to the arm II in any desired position of ad-Justment. The adjustment of the carrier It may be termed a coarseadjustment, since it is eflected by moving the carrier manually on theguide.

On the forward face of the carrier I5 is formed I a dovetail rib Ilawhich flts in'a correspondingly shaped groove Ila formed in a crosscarriage II. On the inner' face of this cross carriage-l1 is a pair ofears I!!! between ,whichflts a gauge mark lob being provided for thegraduations on the cross carriage II. By means of the screw II, I

a fineor micrometric cross adjustment of the cross carrier, andconsequently of the, gauge lever it, may be obtained. The lever I9 isprovided at its forward end with a v-shaped gauge point "a and atits'rear end witha finger piece that between the sides of the threadgroove, for

purposes presently tobe explained. On the inner face of the crosscarriage I1 is a stop 2 la against which the forward arm of the lever I9is normally held by a tension spring 23 which has one end connected tothe lever l9 and its other end held by a screw 22' carried by the crosscarriage II. This stop 2la forms the stem of a feeler dial 2| ofordinary construction, the dial being supported from the cross carriageII. By .this means,

minute movements of the point I90. can be readily observed, even thoughthe point itself cannot be seen.

The point [to of the application has a greater angle than the side angleof the thread groove in the work-piece to prevent notable variations inthe set distance from the center of the point to the center of theproflle center plane of the grinding disk whilea work-piece is beingadjusted; The angle of the point I9a is therefore not immediatelybrought in relation to the normal side angle of the thread groove, sincethe thread groove when prepared to be worked thread to be formed wouldbe problematical.

Isa hasbeen increased over the side angle of the thread groove. Thisgives a greater measure I of accuracy in the setting of a number ofworkpieces at the same time, and the setting is made easier since theangled point Isa touches only on the edges of the grooves. I

Carried by the main or longitudinal carriage 0b is a scale plate 24which moves past a scale plate 25 on the base 9. On these scaleplates'are coopcrating index marks which are so positioned that whenopposite each other, the point "a. will be positioned in the centerplane of the grinding wheel profile. In order that calculations of therequired spacing of the point Ila forwardly of the center plane of thewheel 8 may beavoided, the scale plate is provided with a scale 28 forthreads of millimetric pitch and with scales 30 and II for threadswherein the pitch is measured in the ordinary units, for 'instance,inches. On the plate 25 are index lines 21, 28 and 29 cooperating withthese scales. It will be noted-that these scales have respective scaleindicia 26a, 30a and lid, indicating the number of threads per unit ofmeasurement. The arrangement 'of the scales is such that when it isdesired to set the device for a particular pitch of thread it is merelynecessary to bring the scale line corresponding to the numher of threadsper unit of measurement in alinement with the corresponding indexmark-byro- V m op'eration,.the blank w is placed in the usual chuck(not'shown). The arm II is brought to active position by swinging in ananti-clockdirection and the carrier I5 is manually justed towards thewheel S'and locked in adjusted position with the point I90 in positionto enter the hollow blank. The longitudinal car riage is now moved todisplace the point Ila forwardly fromthe center plane of the wheels.This may be done either by alining the marks 21a and 25a and thenrotating the head Illa until the graduations thereon "indicate that thepoint loa has been moved forwardly a distance obtained by calculation,or from tables, or by alining the proper pitch mark and index line asabove, explained. The head: l8a is now rotated to bring the pointl9ainto engagement with the preformed threads of the blank. Now,by'adjusting the blank along its axial line, a location will be found atwhich the feeler dial indicates the maximum outward movement of thepoint ltd. At

this position of the blank, the thread groove vertically below theprolonged axis of the wheel S and engaged by the point lQa will be amultiple of the thread pitch forward of the center plane of the wheel S.The finger piece Nb is now pressed, the lever i9 drawn. out of thehollow blank and the gauge restored to inoperative position along theline 22. The machine clutchis locked in this adjusted position and themachine started and operated in the usual manner.

'There has thus been provided a simple and tion to the exact form hereinshown and described, but it is desired to include all forms which comewithin the scope of the appended claims.

I claim: 1. In a gauge for positioning internally threaded blanks in athread grinding machine having a --grinding head supporting a grindingwheel profiled to form a thread groove, a'base adapted for attachmentto, said head to extend parallel to the axis of the grinding wheel, amain carriage slidable longitudinally of said base, means to adjust saidcarriage on said base, an arm pivoted to said carriage to swing betweenoperative and point carried by said cross age,

2: In a gauge for positioning internally threaded blanks in a threadgrinding machine having a grinding head supporting a grinding wheelprofiled to form a thread groove, a loose adapted for attachment to saidhead to extend parallel to the axis of the grinding wheel, a main ear=riage slidable longitudinally oisaid base, means to adjust said carriageon said loose, an arm pivoted to said earriage to swing betweenoperative and inoperative positions, a carrier extending transversely ofsaid carriage and slidably adju'stable along said arm, means to securesaid carrier in adjusted position on: the arm, a cross carriage slidablymounted on said carried,'means to adjust said carriage on said carrier,a gauge point carried'by said cross carriage, a gauge lever providing amount for said gauge point at one end and pivoted to said crosscarriage, and spring means urging said lever to tilt in one direction.

3. In a gauge for positioning internally threaded blanks in a threadgrinding machine having a grinding head supporting a grinding wheelproflled to form a-thread groove, a base adapted for attachment to saidhead to'extend parallel to the axis of the grinding wheel, a maincarriage slidable longitudinally of said base, means to adjust saidcarriage on said base, an arm pivoted to said carriage to swingrbetweenoperative and inoperative positions, a carrier extending transjust saidcarriage on said carrier, a" gauge point H carried by said crosscarriage. a gauge lever providing a mount for said gaugepeiot at one endand pivoted to said cross cge, spring in urging said lever to tilt inone direction, and .a feeler dial supported by said cross carriage andengaging said lever to indicate the extent of the tilting movement ofthe lever.

4. In a gauge for positioning internally threaded blanks in a threadgrinding machine having a grinding head supporting a grinding wheelprofiled 'to form a' threadv groove, a base adapted for attachment tosaid head to extend parallel to the axis of the grinding wheel, a maincarriage slidable longitudinally of said base, means to a fiust saidcarriage on said base, an arm pivoted to said carriage to swingbetween'oper-. ative and inoperative positions, a carrier exteud ingtransversely of said carriage and slidably ad justable along said arm,means to secure said,

carrier in adjusted position on the arm, a cross carriage slidablymounted on said carrier, means I to adjust said carriage on saidcarrier, 2, gauge point carried by said cross carriage, and means toindicate the extent of movement of the main carriage on the base.

5. In a gauge for positioning internally thread ed blanks in a threadgrinding machine having a grinding headsupporting a grinding wheelprofiled to iorm a thread groove, a base adapted for attachment to saidhead to extend parallel to the axis of the grinding Wheel, a mainearriage slidable; longitudinally oisaid base, means to adjust saidcarriage on said base, an arm pivoted to said carriage to swing betweenoperative and inoperative positions, a carrier extend-= in gtransversely of said carriage and slidahly adjustable along said am,means to secure said carrier in adjusted position onthe arm, a cross--carriage slidably mounted on said carrier, means to adjust saidcarriage ,on said carrier, a gauge point carried by said cross carriage,and micrometric means to indicate the extent of movement. of the maincarriage on the base.

. 6. In a gauge for positioning internally threadable longitudinally ofsaid base, miorometric means to adjust said carriageon" said base, an inarm pivoted to'said carriage to swing between operative and inoperativepositions, a carrier extending transversely of said carriage-randslide,- bly adjustable along said arm, means to secure said carrier inadjusted position on the arm, a

cross carriage slidably mounted on said carrier,

micrometric means to adjust said carriage on )said carrier, and a gaugepoint carried by said cross age. I O'I'IO

